So, you know how to add, right? Subtraction is just taking the negative one, making it the other direction, and then adding the two in the proper order. So, for example, a 1.00 cm long vector 45 degrees above the x-axis, and the same below it (let the first be a and the second be b, and have both be directed away from the origin). A-B in that case would be the square root of 2, at 90 degrees off the x-axis. The first file I attached was the regular adding, and the second was the subtraction.
